


This was a mistake

by Coniferoussiblings



Category: Gravity Falls
Genre: Comedy, F/M, Sibling Incest
Language: English
Status: Completed
Published: 2018-12-14
Updated: 2018-12-14
Packaged: 2019-09-17 22:49:14
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,458
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16983270
Author URL: https://archiveofourown.org/users/Coniferoussiblings/pseuds/Coniferoussiblings
Summary: At some point in college Mabel jokingly suggests that Dipper should dress up as ‘Dippy Fresh’ for her to fulfill a fantasy, so Dipper ends up going along with it mostly to call her on her bluff, and when he does she doesn’t back down.





	This was a mistake

The bedroom door flew open and Dipper stood silhouetted against the light glaring out from the hallway behind him. The soft yellow glow of the bedroom lamps glinted off the lenses of his neon green sunglasses as he tipped them down over the bridge of his nose and shot Mabel an outrageously cocky wink. The inside of Dipper’s mind was a hurricane of panicked screaming.

_How did I let this happen to me?_

_At what point did everything go so wrong?_

_Okay, just pull it together Dipper… you know she’ll never let you live it down if you chicken out now._

Mabel leaned back against the pile of pillows and cushions stacked at the head of the bed and tried to give Dipper her sultriest look, which still seemed more bewildered than sexy despite her best efforts.

“Why, who is this radical young hunk that just came bursting into my bedroom?” she asked aloud, fanning her face outrageously with her hand.

_Oh my god I can’t believe he actually did it_ , she thought with a mixture of awe and almost crippling secondhand embarrassment.

_I should just call this off right?_

_No… that’s just what he wants. I know he’s gonna crack._

_He’s just gotta._

Dipper strutted up to the bed, red LED lights flashing in the heels of his high-top sneakers with each step he took.

“I’m here because I heard a certain babetacular honey was in the mood for some quality romancin’,” Dipper said, his teeth gritting only slightly beneath his words.

_So this is what it’s like to want to punch yourself in the face._

_I sound like a Ninja Turtle that just had a stroke._

_C'mon Mabel, this has gone far enough right?_

_Why couldn’t she have just had a normal fantasy like getting tied up or something?_

_Who am I kidding? When have Mabel and normal ever gone together?_

“You heard right,” Mabel purred, “but do you really think you are a bad enough dude to rock my world?”

_C'mon Dipper, just bail already!_

_If you call it off now I swear I won’t make fun of you!_

_Probably._

_Argh! Why isn’t he bailing yet?_

Of course Dipper couldn’t bail despite his every instinct shrieking at him to do otherwise. Mabel had broken their sacred treaty and had quintuple-dog dared him to do this, and at that point what choice did he really have?

Even through the haze of the almost painful awkwardness of the situation Dipper spotted the effect that his performance was having on Mabel and felt something like a surge of hope in his chest.

_Oh my god she’s just as weirded out by all of this as I am!_

_Okay, I just have to turn up the heat here and Mabel’s going to be eating her words like cheap candy._

_How unbearable can I make this?_

“The real question is, do you think your bodacious bod can handle the awesomeness of Dippy Fresh?” Dipper said, feeling the gorge rise at the back of his throat when he heard his own words echoing back at him off the walls of the room.

Mabel’s eyes widened.

_Oh I see what you’re doing now… well two can play at that game mister!_

Mabel pressed the back of her hand to her forehead and fell back against the bed like a fainting heroine on the cover of a cheesy romance novel.

“Oh Mr. Fresh, you’re so bold! Speak more of those beautiful catchphrases to me you fly young man-god,” she gasped in a breathy voice.

Dipper winced, her words felt like someone was dragging their fingernails across the chalkboard of his soul.

_Fuck! I overplayed my hand and she caught on._

_Alright, no more messing around._

_Time to break out the big guns._

_God help us all._

“Why should I just speak them, when I can serenade you with some fresh beats worthy of a goddess,” Dipper replied.

_Wait… is he actually going to-_

Dipper began to beat-box extremely poorly, his eyes boring into Mabel’s through the lenses of his cheap plastic sunglasses.

_I’ve got you now sis._

The thought of Dipper trying to awkwardly improvise his way through a radical 80’s slang filled freestyle rap filled Mabel’s brain with complete horror, and in self defense she automatically did the first thing that came to her mind to shut him up.

Before a single poorly constructed lyric could leave Dipper’s mouth, Mabel had shot up from the bed and caught his head in a vise-like grip and then jerked him toward her to smother his lips with hers.

For a second Dipper was frozen in shock, the gears of his mind grinding to a halt at the sudden shift in mood.

_Dear god please don’t tell me that was actually turning her on!_

Before long though Mabel’s frantic kisses had blown the disturbing thought out of his mind. Dipper’s arms had wound up around her slim back as he leaned into her and tilted his head to kiss her more deeply, knocking the blocky day-glo sunglasses askew on his face. Her fingers dragged up under his cap and sent a tingling sensation down his spine as Mabel ran her nails along his scalp and down his neck.

_Crisis averted_ , Mabel thought, palpable relief flowing through her body now that Dipper’s attempted rap had been thoroughly derailed.

Mabel found herself humming into Dipper’s mouth as their tongues met. Even if it had been started as just a distraction the kisses had set a warm fluttering pulse pounding through her veins and she wanted more.

She grabbed tightly to the shoulders of Dipper’s blue lightning-bolt-emblazoned vest and tugged hard, pulling him off balance and sending him toppling down onto the bed next to her. Dipper landed flat on his back and glanced up at Mabel with a small grin pulling up at the corners of his mouth as she clambered up onto his torso, pinning him to the mattress with her thighs as she straddled him.

The mischievous part of Mabel’s mind received a sudden burst of inspiration and she grabbed the sunglasses from where they had fallen onto the bed and settled them firmly back onto Dipper’s face.

“Are you ready to get like, totally weird D-Fresh?” Mabel asked in a husky voice, rocking her hips against Dipper’s to send a shudder up through each of them from the sensation.

Dipper’s hands shot out to grab tightly onto Mabel’s squirming hips and he shuddered to himself, arousal battling with embarrassment at the thought of the oncoming sexual trainwreck that he could see barreling their way if they didn’t stop.

The barest hint of a smirk flashed across Mabel’s face at the sight of her brothers indecision and that crystallized the only real choice in Dipper’s mind in an instant.

He reached his hand up to settle the baseball cap firmly on his head sideways and shot Mabel an answering look of challenge.

“Bring it on,” he replied before sliding his hands up from her hips to her shoulders and pulling her down on top of him.

It got  _weird_  after that.

* * *

It didn’t take long for the fire to finish its job, the box and its contents had been soaked in enough lighter fluid to send up a plume of flame taller than Dipper when he had pitched the lit match into the center of it. The cracked lenses of the neon green sunglasses seemed to stare back accusingly at him from the box before they melted into a puddle alongside the vest and hat.

The flickering firelight cast shifting shadows over the twins faces, but their features were oddly immobile and their eyes unblinking as they watched the cardboard box burn to crumbling ashes.

Once the heat had died down Dipper had kicked dirt over the smoldering remains of the Dippy Fresh costume, only stopping when Mabel had taken ahold of his arm and given it a comforting squeeze.

“It’s okay bro, it can’t hurt us anymore,” she’d said in a soothing tone to him.

“Heh… um. Yeah I was just making sure it was um… totally safe. You know, only we can prevent forest fires and all that,” Dipper said, rubbing absentmindedly at his upper arm and brushing the tips of his fingers against the back of her hand.

“Yeah, I’d say it’s pretty safe already,” Mabel agreed.

The two leaned together in a comfortable silence.

“So we’re never speaking of this again, right?” Dipper asked.

“Oh most definitely. We’re taking this to the grave and possibly beyond that if we get all ghostified for some reason,” Mabel replied.

“Agreed,” Dipper said with a quick nod.

In a quick flurry of fingers and wrists the twins sealed the deal with their secret handshake.


End file.
